Electric burglar-alarm.



N0. 662,657. Patented NOV. 27, |900.

` H. RUHBDANTZ.

ELECTRIC BURGLAB ALARM.

Application med Apr. 14, 1900.) v (lo Modal.) I 2 Sheets-Shoot I j@ @Di/47.

N0. 662,657. Patented Nv. 27, |900. H. ROHRDANTZ.-

' ELECTRIC BUBGLAR ALARM.

(Application led Apr. 14, 1900.)

-2 sheets-sheet 2.

(lo ilodel.)

,UNITED STATES PATENT OFFICE.

HENRY ROHRDANTZ, OF BUFFALO, NE\V YORK.

ELECTRIC BU RGLAR-ALARM.

SPECIFICATION forming; part of Letters Patent No. 662,657, dated November 27, 1900.

vIO

Application filed April 14, 1900.

To a/l iff/mnt it ntf/.y con/cern.:

Bc it known that l, HENRY ROHRDANTZ, a citizen of 'the United States, residing at But'- falo, in the county of Erie and State of New York, have inventednew and useful Iinprovements in Electric Burglar-Alarms, of which the following is a speciiication.

This invention relates to an electromechanically-operated burglar-alarm in which a detonating device, such a revolver,

employed for producing the alarm.

The object of this invention is 1.o provide a simple, durable, and inexpensive alarm ot' this kind which can be actuated repeatedly and at 'lii'ierent intervals, if desircd,\vithout the necessity of resetting the device after each alarm or rewinding the motor which actuatcs the detonatingr device and in which the stop device of the motor can be released with comparatively little power.

In the accompanying drawings, consisting of two sheets, Figure l is a side elevation ofmy improved burglar-alarm. Fig. 2 is a top plan view thereof, the revolver being` shown by dotted lines. Fig. 3 is a dctached vertical section of the motor-drum and its spring. Fig. 4 is a fragmentary side elevation oi the alarm viewed from the side opposite that shown in Fig. l, the revolver being omitted.

Like letters of reference refer to like parts in the several figures.-

A is the base of the apparatus, and A A are two upright parallel frames or standards rising from the base and arranged lengthwise thereof.

B is an upright rotary drum or spring-motor mounted loosely on a transverse shaft or axle b,\vhich turns in openings or bearings formed. in the standards A' A2.

IS is the spring of the motor-drum, arran ged within the latter and secured at' its outer ond to the drum and at its inner end to the drumshaft. y

c isa ratchet-Wheel secured to the drumshaft, and c a detent-pawl which is held in engagement with said wheel by a spring c2. One end of the drum-shaft is square and adapted to receive a key for turning it. The rotary motor-drum is 'provided on one side with an annular row of projecting pins or r tappets d, which are adapted to successively trip or actuate the trigger e of a self-cooking .sena No. 12,806. SNO maan revolver E or si milardetonati ng device which is adapted to be loaded with blankv cartridges. 'lhe revolver is rigidly mounted on a standard F in such a positionthat its trigger standsin the path of the tappets dol' the motor-drum, as shown in Fig. l.

'lhe rotation .of the motor-drinn is controlled by a stop device, .which consists, preferably, of a friction or brake wheel (l and a brakelever II, which is adapted to bear against the periphery ol said wheel. 'lhs brake-wheel is secured to a transverse shaft g,v which is journaled in the standards A' A2, and thc wheel is connected with the motordrum by a suitable train ot' gear-wheels and pinions 'L i", which are so proportioned as to give the brake-lever H a favorable leverage over the motor-drum and enable. the latter to be held against turning by applying` a coinparaI-ivcly small force or pressure to said lcve'r. 'lhe initial pinion' ofthe gear-train meshes with a gear-rim I of the motor-drum', while the inal'pinion i of the train is mounted on the shaft of the brake-wheel G. lhe brake-lever II is secured lo a transverse roel; shaft J, ,iournaled in the standards A A2,

'and its lower arm carries the armature li: oll

an elcctroulagnet K, so that when this armature is attracted b 'the cnervizinnr of the malf- 3'* h b net i he upper arm ot' the brake-lever is moved out ol contact with the brake-wheel G,thercby releasing the motor-drum. The brakelever is normally held against. the brakewheel by a spring L, which is connected at one end to an arm l' ot' the rock-shaft J and at its other. end to an adjustingscrew I?, whereby the tension of the spring can be properly regulated. 'lhis adjusting-screw is arranged in a screw-threaded opening formed in an ear Z3, which projects from the adjacent standard A2. The electrolnagnei' K is ineluded in a suitable electric circuit, the terminals fm m' of'which are adapted to be connected by a suitable makeandbreak device, such as a switch-lever M, when it is desired to operate the burglar-alarm.

In order to cause 4the motor-drum to turn for a greater or less period after the magnet- .circuit has been broken, a supplemental re- IOO ' to perform that function.

'lhsgrctracting device consists of an arm N, secured to the rock-shaft .l and provided at its free upper end with an inwardly-cxtending lip n, which is adapted to .ride on au annular flange o, arranged on the periphery of the motor-drum. This ange is provided at intervals with notches or recesses of, which receive the lip ofthe retractingarm N and which are of such a depth that when said lip rests in one of the vnotches the brake-lever is permitted to swing inward sufficiently to bear against the brakewheel. The rear ends of these notches are beveled so as to form cams o2, which pass under the lip of the rctracting arm N as the drum rotates, thereby raising the arm to the edge of the flange o, on which latter it rides until the next notch of the fla-nge arrives op posite said lip, when the .arm is swung inwardly into the notch oy the action of the spring l.. 'ihe reti-acting arm is thus held in its elevated position by the flange o during the time` that; the drum turns a distance corresponding to the interval between two successive notches of the flange, and the retracting arm in turn holds the brake-lever out of contact. with the brake-wheel during the same time. i

My improved burglar-alarm is designed rto be used in connection with an electric callbell arranged in a circuit which is normally open,but is closed bysuitable make-and-break devices arranged on the adjoining portions of' the window frames and sashes or the doors and ,iambs of the house,so that as soon as a sash or a door is opened without authority the callvdevices M is designed to bc located in e'aeh bedroom of the house, and these switches are normally open, as shown in Fig. l. In the normal position of the 'parts the retracting arm N rests in one of the notches o' of the drum-flange o, thus allowing the spring l to hold the brake-lever ll against the brakewheel and holding thc motor-drum against turning under the action of its spring. When the call-bell referred to gives an alarm, indie dicat-ing that-.a` dootl or window has been opened,one of the occupants closes the nearest switch M, thus closing the circuit. containing the magnet K. The attracted armature ol the magnet swings the brake-lever ll out of contact with the brake-wheel (l, thereby rcleasing the motor-drum and allowing it to tu ru. The tappet l of the drum immediately in front of the trigger 'of the revolver E now trips the trigger, thus discharging one of' the blank cartridges and giving a loud report, whicltis calculated to frighten the burglar away." The rotation of the drum causes the retracting arm N to be raised and ride on to fire the revolver upon operating the alarm.

Should there be reason to believe that the first shot has not had the desired effect, the switch M may be again closed for firing one or more additional shots.

If desired, some ofthe notches ofthe flange o may be arranged at such long intervals that the motor-drinn permitted to turn far enough to cause two or more of its tappets'to trip the trigger before being stopped, thus causing a correspond-ing number ot shots to be fired for one actuation .of the yfarm device.

'ly this construction thealarm may be repeated until the cartridges nare exhausted without requiring the motor to he rewound for each alarm or necessitating the resetting of the alarm devices, it being only necessary to rewind the motor when its springbecomes too weak to trip the trigger of the revolver and to reload the revolver.

In order to prevent the release ofthe motordrum in case the armature c should be touched accidentally, the notches of the flange o are iliade comparatively long, so that one or two quick vibrations of the armature-will not allow the motor-drum to turn a sufficient distance to raise the retractin'g lever out of a notch of said flange. l

In my improved alarm the revolver is op crated directly from the spring-barrel B, thus utilizing the power. of the motor to the best advantage and permitting the use of a correspondingly smaller and less powerful motorsphrinv. As the motor-drum isnormally held against turning by a brake-lever aud a friction-wheel, which latter is geared to have a favorable leverage over the motor-drum, compa ratively little power is required to prevent rotation ol' thc drum, and the power required to release thc brake-lever is therefore correspondingly reduced. lhis frictionai stop device also has the important advantage of per-v mitting a comparatively rapid rotation of the motor for producing a prompt alarm and of allowing an abrupt stoppage of" the motor without causing breakage of the teeth of the gear-train or other parts, which is liable to occur when the motor is suddenly arrested by a positive stop device.

lclaim as my inventionl. ln a lnu'glar-alarm, thel combination with a rotary umtor-drum having one or more tappcts, and an alarm device having a trigger or actuating member arranged in thc path of said tappets, of an electric circuit containing a make-and-break device and an electromagnet, a friction-wheel connected with said niotoo IIO

tor-drum by intermediate, gearing, a brakelever bearing against said friction-wheel and connected with the armature of said electromagnet, means for yieldingly holding said brake-lever against said friction-Wheel, and a retracting device for said lever which is supplemental to said armature and which is operated from said motor-drum, substantially as set forth.

2. `In a burglar-alarm the combination with an alarm 'device having a trigger or actuating memberof a rotary motor-drum having a notched annular flange and one or'in'ore tappets arranged to trip said trigger, an electric circuitv containing a make-and-break device and an electromagnet, a friction -Wheel geared with said motor-drum, a brake-lever bearing against said friction-wheel and connected with the armature of saidvelectromagnet, a

retracting arm connected with said lever and bearing against said notched iiange, and means for yieldingly holding said brake-lever against said friction-wheel and said retractling arm against said notched flange, substantially as set forth.

3. In abnrglar-alarm, the combination with an alarm device having a trigger or actuating i member, of a motor-drum having a notched annular fiange and one or more tappets arranged to trip said trigger, an electric circuit containing a make-and-break device and an electromagnet, a friction-wheel geared With said motor-drum, a rock-shaft, a brake-lever mounted on said rook shaft and bearing against said friction-wheel and carrying the armature of said electromagnet, a retracting arm mounted on said rock-shaft and hearing against the notched ange of the motor-drum, and a spring connected with an arm 0f said rock-shaft and tending to hold said brakelever against said friction-wheel and said retracting arm against said notched ange, Substantially as set forth.

Witness my hand this 9th day of April, 1900.

HENRY ROHRDANTZ.

Witnesses:

JNO. J. BONNER, CYESTA HORNBECK. 

